Grinding machine for operating upon workpieces



April 6, 1948. H. N. sEYFERTH 2,439,105

GRINDING MACHINE FOR OPERATING UPON WORKPIECESl Filed oct. 2, 194s e sheets-sheet 1 April 6, 1948. H. N. sEYFERTH GRINDING MACHINE FOR OPERATING UPON WORKPIECES Filed oct. 2, 194sl e sheets-sheet 2 INVENTOR. Haro@ l( /u/er,

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GRINDING MACHINE .FOR OPERATING UPON WORKPIECES 6 Sheets-'Sheet 3 Filed Oct. 2, 1943 April 6, 1948. H. N. sEYFl-:RTH

GRINDING MACHINE FOR OPERATING UPONy WORKPIECES 6 Sheets-Sheet 4 Filed 0G11. 2, 1943 4 /OZv H81, /la

6 ZOb 20a 2 o 24 /aaa INVENTOR. Haro/c 7l, {ej/M BY April 6, 1948. H. N. sEYFERTH GRINDING MACHINE FOR OPERATING UPON WORKPIECES Filed oct. y2, 194s e sheets-sheets INVENTofR. i x /czrofc KJvfe 11% HTroP/VEY,

April 6, 1948. H. N. sEYFER'rH GRINDING MACHINE FOR OPERATING UPON WORKPIECES 6 Sheets-Sheet 6 Filed 06.11. 2, 1943 R O T N E V m HAROLD Al. Serf-fern ATTO RNE YS Patented Apr. 6, 1948 i s439906. t GRINDING MACHINE Fon OPERATING i VUPONWoRKPnioiizsm.TM "-9 Harold N, Soyfrtii. 'East Detroit, Mich., assignor "toE Cell-t0'Corporation,D'etiog'Mich fr por ion @Michigan v i -Aiiittioti iioto'btf '2, 194s, soria; No. 594.@ aan "tenista (c1.5i;9'51

invention relates `geI-rerally tov improvementslin ngrindi g' inalnes for` operating u'p`n Workpieces, "andinas iitility"asL `an'iadunct to' a grin' ing machine in grinding oi thread milling hasta@ttsittttinstdsts fatali-estacion upon the' leading edge of multiplicity of asso# ciated spiral chipK cle4 ariete".gfadslres"A equally sincedarouridiheRenner..of ihs'fhb.; The relived trailing portions" of the respective-l teeth en'lnin tneadiacelflt; spiral gash which trails the' cutting edges oi tlieteetli. The angle of these spiral gashes, 'made with an element of the generally cylindrical peiiphe'ralisurface of the hob, usuallyis from 3 to 10J respectively correspondingit'oif iislsrtgiesoftito'eo'f' m `en"`elieifiijg" tlirad'f'n'illing h obs, the tool whitii'-oitts'tnsr1i' odftootn sufaoefoontats the 'j f@ itsV agri's'o rotation wheiis'enrating; th 1\fiuiv'i'risiffdlg mail at :any relieved'- portion of the tooth l 'which trails this portionvoi maximum radius. "Injtl'i'e relieving of straightjga'shedztliread millinghobsi the relievingf `isuallr a""iQtt1g,^complern'entai'ily formed grinding' 'W"eel)" describes" an' 'exactly' and'` synch on 1y^timeqfniov9ment of reciprootttion with resp to trirotation ofwthohob being r-eii'eoggth'e initoolgmakiiigtts many oyoiss` ofj recifird l n 's' there are equally' spaced gsiies around t a v i c tno'reiieifing 'of' tn testi; fspintuy gasiied itobs,v thefsttmf timing' of relieving 'movements of the toot` 'must osisitwitn res `@ffii to tooth of etch rowta n longthe leading "spiral edge of the chip clearance y gash `of the lion.K To accomplish this result there must be a brdtermine'd clange' 0f... timing between .the rpiati 'Of "ili'hvb 'and the `positioning oiitli'elrlievinghtool axially of the hobiwin 'each posiimnigff the fgrinldilg Whel along the lobjaxis,j which timingl change must be in accordance with the helix angle-ofxtheispiral gashes in the hob surface. It is'anobjec't of the prsent invention to' automaticallii, accomplish thtimingchange *between ne circuiti-f noie oitii'ho'b". In

liic

grinding Spiral gash@ or such lcuttin too v ohinshown in Fig.

with facility to bringfin'to coinciden-oo no iii'iti'if timing relations required Vbetween mov axialfseparatin between Wheel axisas required in `et grinding" machine t In the drawings: Eig. l is a frontV ttt-s Fig. B is Aa fragment y se ional View through tho machins f'siiir'ta afafl an meansas'se'en on 1i e f s-oiFigim Fig. 101st fragmentary sectional view on lines lol-ro Nof Fig;` I3 'w'itnftttilstbokfriiitte for" claritin' Fig; 11` is a fr a'gmiitr'y' sectional oiiiines HLltof Fig. izgfttndff A Fig. izis a'. persootiye view of the rsiie'ving means shown ttssociatiolwitn the" machins' tameqofFiss. 'Referring' more particularly to the' drawings; Figi 1` shows `wen machine the principal' a stiu'otiirm ffaturs'sjfr described "in United i stats Patent No. 2,251,261," issued. August 12, 1941, tonta Jissdr; lAstho esent triventioriis susceptible to usowttngridiiig insistimos of l Various constructions, it` iss'cie'nt to say' that "'iiittonin' siii-tools for fsf tiierowith irioliids s'base 23a ti'l siiaabi thereonlong-itudittuy of the df tito wtrkpieofwin' tt stopV igt 9 is it fragmentary seoti'o '1 new oit iin'sy thereof -iteniidialtetii giri-iiding1-offsoigns-site;

3 teeth on the workpiece W as required by the pitch or axial spacing of the teeth along the workpiece.

Back of the table 4 and mounted on a cross slide 8 is a conventional belt or electric motor driven grinding wheel means I having a wheel I2 which is complementarilyforcmed to grind into the periphery of the workpiece a groove or thread convolution of the desired shape. The cross slide 8 may be moved transversely of the axis cf the work W by a work size control wheel I4. The wheel infeeding movements may be accomplished either automatically or manually as desired. l n

On table 4 is mounted anauxiliary table I 6 provided with a rotatable and rockable work support I8. The purpose of the rockable work support is to successively rock the rotating work toward and away from the rotating grinding wheel in as many duplicate, complete and properly timed cycles of relieving movements of approach and-recession as there are gashes or numbers o-fteeth in one circumference of the work, to the end that all of theiteeth in a given row or convolution may be properly and identically relieved.

The rocking work table last referred to is fully described in applicati-on Serial No. 481.993, iiled Anril 6 1943. by Harry Egleston (now Patent No. 2,379,287); only sufficient of the' description will be repeated here to describe one illustrative ernb-odiment of the present invention.

Referring to Fig. 3. the table 4 is provided with a rotatable hollow spindle 20 which may be power driven in any desired mannerv as bybelt drive from conventionalmotor means (not shown) to worm shaft 22 meshing with worm wheel 22--a which Ais keyed to spindle 20. On the face of spindle 20 is fixed avdrive gear 24 which drives gear 26 which in turn is mounted on shaft 28. The rightward end of shaft 28 is supported in the inner race of a ball bearing 30 which has its outer race supportingly surrounded by a bearing sleeve 34 `which is fixed in auxiliary table I6. At its leftward'end, shaft 28 is supported in needle bearing :i2-whichv is` surroundingly supported in bearing sleeve 38 fixed in frame 44. Spigot formed portions of sleeves 34 and 36gare supported in the inner races of ball bearings 42 adjacent the rightward and; leftward ends of shaft 28. The outer race of the bearing 42 adjacent theleftward end of said shaft'is supported in a boss 40 of auxiliary table I6, and the like numbered bearing adjacent the. rightward end ,of the same shaft is supported in like manner in frame 44. On these ball bearings 42, the frame 44 is pivotally supported for oscillation about the center cfs-haft 28 asA an axis thus permitting the workhead I 8; which is supported by frame 44, to have its relieving movements relative to the grinding wheel I2. Shaft 28 drives a train of pick-off gears 46 which in turn drive a shaft 48 on which is mounted a relieving cam 50 which is driven ata speed which is a multiple of the speed of workhead I8. The order of this multiple is determined by the number of chip clearance gashes onfthe workpiece. The purpose of cam 50 is to cause one complete oscillation of approach and recession of the axis of workhead I8 toward and away from the grinding wheel I2 for each tooth on the workpiece which is presented to grinding wheel I2 in one revolution of the work W. The cam 50 is adapted, by means shown in Fig. 9, to rock the frame member 44 in one complete cycle of relieving movements per revolution of said cam.

' 4 The spindle shaft 52 of workhead I8 is formed at its inward end as a driven member 54 of a conventional Oldham coupling. The central member and driving end member thereof are i numbered B and 58 respectively. Member 58 is keyed to shaft 60 whiohextends through hollow,

spindle 20 but is movable laterally in relation thereto for the reason that the hub of member l 58 is journaled in the axial bore of gear 24. The

Oldham coupling previously described, therefore, allows work spindle 52, which supports workpiece W, to be driven by shaft 60 while being continuously oscillated out of co-axial relationship therewith by the action of relieving cam 50 upon the pivotally mounted rockable frame 44. In the environmental views, Figures 9 through l1 inclusive; Fig. 9 is a fragmentary cross section through the machine table and the relieving device showing the cam 50 by which the rocking table 44 is oscillated and control means 8,6,nful1y described in aforesaid Egleston application, Serial No. 481,993, by which the amplitude of such oscillation may be adjustably predetermined. A

Fig. 10 shows a `section through the machine table 4, the support for the relieving means including the screw and nut means 62 by which the auxiliary, table I6 of the relievingdevicefis fastened to the machine table 4.

Fig. 11 is a fragmentary cross section through,

the machine table 4V and the relieving device showing control means 64 for stopping the relieving movements thereof when desired.

Phase control device 20 may be altered, with each change `in longitudinal position of machine table 4, as required for properly relievingthe teeth of a spirally gashed workpiece W.

This device includes a housing |02 which is held on hollow spindle 20.by a key 20-a and a nut 20-b for rotation therewith. The housing |02 is formed with longitudinal .faces |04 into which are sunk oppositely extending ears |05 of a transverse member |06 and fastened to the housing |02 by dowels |01 and screws IUT-a. This member is formed with a bore |08 co-axal with spindle 20, housing |02 and shaft 60. The shaft 60 has a stepped end of reduced diameter which is journaled in the bore |08 and is anchored against end motion therein by opposed thrust washers IIO and a pair of lock nuts |I2 by which the thrust working clearance may be adjusted and locked.

To the right of nuts |I2, the shaft 60 is again shouldered as at I|5 and reduced in diameter to form a support ||3 for a split clamped member II4 mounted thereon against the shoulder and held in position by a cap |l4-a and screw II4-b.

On each of the housing faces |04 are xed, by suitablescrews, a rabbeted strip ||6 forming a slideway for-.receiving outwardly extending ears I I1 of a frame I|8 which is slidable axially of housing |02. The rightward end of frame IIB is formed with a lug I 8-a which is formed with an axial bore IIB--b faced at its opposite ends. Through this bore a shoulder screw |20 is threaded into a tail rod |22 and locked thereto by screw |20-a, The shoulder I I 9 on the screw |20 vand an opposed thrust washer |20- b bear respectively on opposite sides of lug |8-a and permit rotation of 'device |00 about the axis of the asf bracket |26 and locked in adjusted position-hy" Tarif ibracket liziir` .isfvfastenedz to. the base; 1.of` thaimarchinesanm since;A means lllftogethery with: itsgdriving spindle 20 1 and the-- auxiliaryltable IfGa carryingrthe.:worlchea-d-|=8L are; carried;` oir` slidable tablef 4;, it isseen: that eachfy movement- Gif-thetable, causes;` cam: Vfollower:-lfHl-cz tm move along: theaedge t 12b-aofi HM.4 'l'hiszzcausesiishaitf Sii-tor experience af lclfiangev in angular relationtoi :spindle 29, the;V relieving, means 'whichi rocks theawork: W in: relation-` to ther-grinding" wheel |--2f'isactuated:in,r spindle 20? througlrmeans1 previously ydescribed.-and-`V the workhead |81 is drivemthrough the; angular changel devicey :|;0 il; iti-may;h `lie-seen that; eachaxiali movement tabled will make arpredeterminedixehange ct'. angular? relationff between: the." work Wand the; mov-ement` of; theirelievingfmeans.. The magni-l tudes of` .thief vangular `chan-ge,` iper. :unit ot table: movementn mayffhez alteredv by alteringr the :adjustment.off;l cam |12# or bysub'sti-tuti'ng thereforV camsv having; 'diierentz inclinations. of.their1f-acesrv IZA-eavv'ith,respect` to thefaxls; offlinnsing` H12.

The adjustment@ofl tail; ro'dl22in hraclietv mi;

maltais-possillef lthe propercointidence of the maximum separation ofrwork axis and grinding Wheel axis lncsei'itingV upthe-machine so that, in'their cyclical;relievingv movements; .theA cutting edge of the tooth may be groundft'oea largenfdiameter thananvl portionvoi the toothwhich trails the cutting'edge.

Forfipurposes of appearance and protection' from; abrasive, grit housing` H12" is provided ana. end closure cover to2-d andrajface closure fille-b.. t

IShmmarizing the operations pertainingftd-:the angular `changeM meansY iir the grinding ofi 1nd lead: spirally gashed. threadrmilling hobszflfie: work; is. mounted for rotation` by the work.- headi it the` cam |24 is.adustefdfto' correspond? to` the-helix angleh of the spirali gashesvi'n the work W. the tail rod |22 is adjusted in its bracket in desired coincidence with the cutting edge of the tooth. After the making of the foregoing adjustments, no further attention need he given the angular changing means as each axial movement of the machine table 4 will cause the required angular change between relieving means and work rotating means.

While the present invention is illustratively shown in connection with the grinding of no lead thread milling hobs, it is to be understood that it is adapted for use in the grinding of spirally gashed taps and similar lead threads if desired. In fact the invention is susceptible to many modiications and alternative constructions and the I to bring the high point of the tooth diameter bisthaianpemdediy claims.. :Iflelainnas'mtiiiiventlnnz:

In mmaciiineifor -cuttingrelievedtooth con.-

onrthee periphery ci? ai. thread miilingf heb.: havingffspirailrtootlr face; gashes, combinationgrrarl'basei, ai tableatranslamblei thereon', a. cut,- ter:onerativety''sllpllidiomsaidhase, arotatabl'e; imounted on: saith ytalrle for rotativelyv sunportingrther-hobtm; operative association with the means torl rntatiizigzl the:- workliead, relieving means operatively connectedA to said rstvmientioned means iforei'ecting relative approach and receding movements between said' cutter: fsaidi worlohead :to alter the radial distance-nom me cutter to. the axis: or the heb im ai Asuccession oi-nelativei tooth: relieving' movementsibetween ysa i'eutter' and saidf -workhead' initimed relation th the rotation i of' the Workhead?,V main' power `meansincluding a hol"- lovw lrotatai'rii'v fsupported lon: said table, means-fer drivingsaidshait,`fmeans at onel endf oi? said' lsiuiiit for drivingn` 'thev toothrelieving rneans, a housing fixed to'Y thev opposite end' 4of said-'hollbwisagtii-foif rotation therewith, a frame rotata'bihi driven bvs'aid'housing and axially slidabletherewitfiin, a tairrod'journaied at one end thereof to said trames-aridi anchored to said hase-- shaz-tir'with-in-v saiid* housing engagingV the edgeof camiiol'otationally drive said inner shaft` uponrotation*of'said1` outer straft',` coupling means interm'edi'ate'fthe`- opposite'i-endro said'` inner shaft and: thei worliheadi 'to4 drivesaid workhead fromV said inner" shaft, and means2 `for adjustably positioning said' plate cannon said frame to change theVetFecti-veness of"saidc`am= to alter the timedrelation.i of" therworlr` rotatihga-nd` the relieving in comhinatibn: asupport, a power input shaft;

arpower outputshait, one of; saidshafts being conoentricallydisposezf withinA the other' throughh ouia portionV or its length vand beingangulariyoscillatable therewithin, a bearing carried by saidJ support, said snaft`s-teing-rotatabie `insaid bearing; ai housing iixeii toione'end of the outer shaft forirotation therewith; 5a; member rotationally driven by the1 housingand movable-axially there-` of; tail shaft `means coaxial-'with said"A shafts-andjournaled @said-member toeii'ectrelative move-r merit ofifthe' saine-'faxiallyof* said housing;v an edge plate* cam' adjustably' fastenedto saidl mem'- ber,` ja: portionf oft said i innershaft extended withinfsaidi-housing' andrhavin'gfxed" thereto a; camfollower to engage the edge of the plate cam when said member is relatively moved axially of said housing, spring means urging said follower into engagement with said cam, and means for altering the adjustment' of said cam on said member to alter the effectiveness of said cam in causing relative angular movement between said two rst mentioned shafts upon relative movement of said member axially of said housing.

3. Means for altering the timed relation of a 'rotationally driven `device relative to a driving device associated therewith including, in coimbination, a support, bearings on the support, a pair of shafts rotatable insaid bearings, a member xed to one of said shafts having a slideway formed therein, a member slidable on said slideway and having a 'cam surface, meansforl effecting relative movement 'of said slidable member along said slideway,` a member fixed to the other of said shafts and having a cam follower fixed thereto for relative traverse along the cam surface when the slidable member is moved relatively along said slideway, said cam and earnv foi lower fbeing effective upon relative movement therebetween to alter the angular'position of one of said shafts relative to the other, a connectionv joining the driving device to one of the shafts 'and a connection joining the driven device to the other shaft of said pair.

4. In a machine for cutting re'lieved tooth convolutions on the periphery of a thread milling hob vhaving spiral tooth face gashes, in combination, a base, a table rectilinearly translatable in a predetermined direction, a cutter mounted on said base, a workhead having a rotary spindle disposed parallel to the direction of table translation andV adapted to support said hob, said workhead being mounted'on said table for translation therewith and for relieving reciprocation transversely of said spindle toward and from said cutter, a relieving cam operable to impart said relieving reciprocation to said workhead, and power transmission means having a driving shaft operatively connected through two parallel 'branch transmissions respectively for driving said spindle and said cam in timed relation` whereby to obtain one ,relieving reciprocation for each tooth'of a tooth convolution of said hob, one branch transmission including a driven shaft coaxial with -said first shaft, said shafts being supported on said table for axial movement there-- with, a cam mounted on said driving shaft for rotation therewith 'and for relative sliding movement axially thereof and having arcam face extending generally longitudinally of the shaft axis and being selectively adjustable into various angular relations to` said axis, a cam followerV connected to said driven shaft for rotation and translation therewith, said follower slidably engaging said cam face and establishing a rotary driving connection between said shafts, and means adjustably connecting said cam to said base to constrain said cam against movement with said driving shaft upon translation of said table.

5. In means for rotatively cutting parallel circumferential convolutions on theV periphery of a thread milling hob having spiral tooth face gashes, rotary convolution cutting means, means for supporting and rotating the hob, means automatically and cyclical'ly operable'in timed relation to the rotation of said hob supporting and rotating means to effect relative movement between said cutting means and said hob supporting and rotating means transversely Yof the hob axialmovefments'of the hobsupporting and rotate ing meansfrelative to the cutting means to' alter the angular relation between the rotative relationI of the hob supportingand rotating means and' the means for effecting said Icjrrclica'lrelieving movements.' l

6. A power transmission mechanism including in combination, a supporta power inputshaft,"a :power output shaft coaxial with said input shaft and coextensive therewith throughout "a portion of their lengths, a bearing on said support, said' shafts being rotatable in said bearing, a'. bearing permitting angular movement of-"said shafts relative to each other, a housing fixed ono'ne 'of said shafts for rotation and axial' movement therewith,

a frame rotatable with said housing andrelatively axially movable therewithiri, 'tail' shaftfmeans connected 'to said frame to constrain'the same against axial movement' with fsaidhousing, "af plate cam adjustaibly fastened tosaid "frame, aj

cam follower fixed to thevother of. thev said' two first mentioned shafts and positioned' within said housing for longitudinal movement' relative to' the edge of said cam when said'housingis moved axially relatively to said frame, andmeans for altering the adjustment of'said cam on said frame to alt'er the'eifectiveness `of said'cam in causing relative angular movement' between said`v two rst mentioned shafts upon relative-movement of said frame in said housing.v l 1 HAROLD N. SEYFERTH;

REFERENCES CITED I The following references are of'A record the file; of'this patent:A l v Y v UNITED sTATEs PATENTS. Y.

Number Name *Date 1,027,644 Diemer Mayl28, 1912 1,629,252 Bouza r May 17, 1.927 f 1,640,994 Hanson Aug. 30, 1927' 1,835,476 Drader Dec. L8, 1931 1,983,286 Godziewski Dec. 4,' 1934 2,057,354 yWithers et al. Oct. 13, 1936 2,079,785 Ackley May 11, 1937 2,190,900 Von Tavel Feb. 2 0, 1940 i 2,227,715

Horstmann -1 Jan. 7, 1-941 

